Krishnarajasagar Reservoir

Country/territory: India

IBA criteria met: A1, A4i, A4iii (2004)
For more information about IBA criteria, please click here

Area: 12,500 ha

Bombay Natural History Society
IBA conservation status
Year of assessment (most recent) State (condition) Pressure (threat) Response (action)
2013 favourable medium negligible
For more information about IBA monitoring, please click here

Site description (2004 baseline)
The 12,500 ha Krishnarajasagar reservoir was formed by impounding the Kaveri river at Kannambadi in 1924. It is located at the confluence of three rivers, the Kaveri and its tributaries the Hemavathi and the Lakshmanathirtha. It was one of the earliest large dams constructed in India and at present irrigates 0.4 million hectares of land in Mysore and Mandya districts of southern Karnataka. Large marshes form at the points where the rivers enter the reservoir. They come into existence every year as the reservoir fills up by September, and are used by thousands of migrant wader birds on passage. The marshes and mudflats expand as water is withdrawn from the reservoir for irrigation and they are at peak in December-February. Fields of millet, sorghum and vegetables are cultivated around the reservoir. The floodplain marshes are used in summer to cultivate vegetables. During monsoon, water lilies are cultivated for their edible roots.

Key biodiversity

AVIFAUNA: This site is very important for congregation of ducks and waders in the region. It supports large flocks of Northern Pintail Anas acuta, the annual total of which exceeds 15,000. It also supports substantial flocks of at least 500 Bar-headed Geese Anser indicus and over 1,600 Brown-headed Gulls Larus brunnicephalus, more than their 1% threshold limits of 200 and 1,000 respectively (see Wetlands International 2002 for 1% population thresholds). Huge flocks of waders, numbering in thousands, winter in the marshes. These include over 3,500 Little stints Calidris minuta and 2,000 Temminck’s stints C. temminckii, both over their 1% biogeographic population threshold mark of 2,000 and 750, respectively (Wetlands International 2002). During normal rainfall years, waterfowl counts vary between 25,000 and 29,000 birds (A4iii criteria). During the spring migration from late March to early April, the wader and duck numbers swell up to 50-70,000 for a couple of weeks. Sometimes, these include over 10,000 Common Pochards Aythya fuligula. The reservoir marshes are most important as the wintering ground for a large number of Greater Spotted Eagles Aquila clanga. In January 2003, T. Shivanand counted 19 birds (pers. comm.). Every year, between 6-8 birds can be seen in the reservoir. The dry fields around the reservoir support enormous flocks of Rosy Starlings Sturnus roseus (>7,000 recorded), Greater Shorttoed Larks Calandrella brachydactyla (>2,500 seen) and smaller flocks of migratory Blyth’s Pipit Anthus godlewskii, Richard’s Pipit A. richardi, Tawny Pipit A. campestris and Tree Pipit A. trivialis, as well as the Red-headed Bunting Emberiza bruniceps and several wagtails Motacilla spp.

OTHER KEY FAUNA: No information.

Key contributors: Thejaswi Shivanand and A. Shivaprakash.

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Krishnarajasagar Reservoir. Downloaded from on 04/10/2023.